1. Field of the Invention
The present invention relates to measuring the geometry, especially the surface contour, of elongated members and particularly to the detection of undulatory wear of rails. More specifically, this invention is directed to a portable instrument for detecting corrugations in the surface of a railhead. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well suited for the measurement, in the field where external power sources are not available, of the undulatory wear of the rails of a railrod track. The need for measurement of rail geometry, and particularly uneven railhead surface wear, has long been recognized. U.S. Pat. No. 4,075,888 to Buhler contains a discussion of the need for such undulatory wear measurement.
Presently available devices for use in rail surface contour measurement are exemplified by above-mentioned U.S. Pat. No. 4,075,888. These wear measurement devices are typically mounted on some form of supporting platform which continuously moves along the rail. This continuous motion results in the platform being subjected to the very condition which the measuring device is intended to gauge. Accordingly, the wear measurement devices available prior to the present invention have been characterized by considerable complexity incident to attempts to compensate for the track induced movements of the platform on which the measuring device was mounted. This apparatus complexity, in turn, greatly increases the cost of the equipment and also increases the level of skill required of the operator while simultaneously diminishing the reliability of the measuring equipment.
A further deficiency of prior art surface wear measuring devices has resided in an inherent inability to relocate the device on the rail in precisely the same longitudinal position where a previous measurement was performed. Thus, in actual practice, the prior art apparatus had the capability of making a measurement only in a single vertically oriented plane extending through the railhead.